Malicious PDF — malware analysis report

Static analysis result for SHA-256 66e90ced46cf69dc…

MALICIOUS

PDF

5.7 KB First seen: 2013-01-23
MD5: 98c8bfb4847350c76bf08c91e82c1825 SHA-1: 973e0407fb0a983615353ba718e7cfc02024247f SHA-256: 66e90ced46cf69dc43e27966c66ebc0340eb1c09c3917066822cf3fdb41b38fe
72 Risk Score

Malware Insights

MITRE ATT&CK
T1059.007 JavaScript T1566.001 Spearphishing Attachment T1203 Exploitation for Client Execution

The PDF contains a malformed stream length and an embedded script payload, strongly indicating an exploit attempt. The ML classifier also flagged this PDF as malicious with high confidence. The embedded JavaScript is likely designed to download and execute a second-stage payload, as suggested by the embedded file artifact.

Machine Learning

  • Nyx PDF Classifier malicious score 1.0000

Heuristics 6

  • Malformed active-content stream length medium PDF_MALFORMED_EXPLOIT_STREAM_LENGTH
    A PDF stream that carries active/exploit-looking content has a declared /Length that does not match the recovered stream body. Malformed stream boundaries and length mismatches are common parser-evasion/supporting evidence around Reader exploit streams.
  • Embedded file low PDF_EMBEDDED
    PDF embeds a file attachment — could carry an executable or another weaponised document as a nested payload
  • XFA form low PDF_XFA
    PDF uses XML Forms Architecture — can contain script logic
  • Embedded script payload in PDF stream info PDF_EMBEDDED_SCRIPT_PAYLOAD
    PDF stream bytes contain an HTML/XFA <script> tag without accompanying Windows shell-execution primitives — common in accessible XFA forms but worth surfacing for analyst review.
  • Suspicious extracted artifact info EXTRACTED_FILE_STATIC_TRIAGE
    One or more files extracted from inside this sample matched static suspicious-content checks such as script obfuscation, encoded payload blobs, packed data, or execution/download terms.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://ns.adobe.com/xdp/ In PDF document text
    • http://www.xfa.org/schema/xfa-template/2.5/In PDF document text
    • http://www.xfa.org/schema/xfa-data/1.0/In PDF document text

Extracted artifacts 1

Files carved from inside the sample during analysis.

FilenameKindSourceSize
embedded_file_obj0008.bin pdf-embedded-file PDF EmbeddedFile object 8 at offset 0x78 5113 bytes
SHA-256: 33b601e66d2b2888584404610ac560cde45135f8a72a478b79be499689418357
Detection
ClamAV: No threats found
Obfuscation or payload: likely
Carved artifact contains 4 long base64-like blob(s).

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